<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<style>
.a2{
    width: 402px;
    height: 82px;
    border: 1px solid gold;
}
.a2>.a3{
    width: 60px;
    height: 60px;
background-color: #90ee90;
float: left;
margin: 10px;
}
.a2>.a4{
    width: 60px;
    height: 60px;
    background-color:pink; 
    float:right; 
    margin: 10px;
}

</style>
<body>
    <div class="a2">
<div class="a3"></div>
<div class="a4"></div>
    </div>
</body>
</html>